I published the same criticism in relation to one of their earlier summaries. Backblaze responded with something along the lines of (paraphrasing liberally)

> We're giving you this data for free and providing a brief summary of what you should expect to see in it. We do not get paid to teach our readers advanced statistics, nor is that what we want to do. We encourage you to take the raw data and explain to people how you think it should be analysed.

which seems like a fair response. I'm very, very grateful that they release the data freely the way they do. It reflects well on them and more companies should do that.